5 -Adenylic deaminase, application

S -Phosphodiesterase Several reports have appeared describing the semi-industrial scale application of immobilized 5 -phosphodies-terase for production of S -mononucleotides (IMP, AMP, GMP, UMP, CMP) to be used as flavor enhancers (30,41,42). In Japan, the enzyme is immobilized on a porous ceramic support and used (in combination with a similarly immobilized 5f-adenylate deaminase to convert AMP to IMP) to produce the S -mononucleotides from RNA (30,41). The deamination is desirable since IMP and GMP act synergistically with monosodium glutamate as a flavor enhancer. 

Due to the importance of modified nucleosides that are also in the base, the development of new biocatalytic processes appUed to the synthesis of derivatives modified in the base is of great interest Adenosine deaminase (ADA) and adenylate deaminase (AMPDA) are biocatalysts that catalyze the hydrolytic deaminahon of purine nucleosides and nucleotides. Some applications of these deaminases for the preparation and transformation of compounds structurally related to nucleosides with potential antitumor and antiviral activities have been described in the last few years [8]. 

Fishbein, W.N. 1979. Indicator enzyme assays. I. Adenylate deaminase principles and application to human muscle biopsies and blood cells. Biochem. Med. 22 307-322. 

Several enzymes have been immobilized in sol-gel matrices effectively and employed in diverse applications. Urease, catalase, and adenylic acid deaminase were first encapsulated in sol-gel matrices [72], The encapsulated urease and catalase retained partial activity but adenylic acid deaminase completely lost its activity. After three decades considerable attention has been paid again towards the bioencapsulation using sol-gel glasses. Braun et al. [73] successfully encapsulated alkaline phosphatase in silica gel, which retained its activity up to 2 months (30% of initial) with improved thermal stability. Further Shtelzer et al. [58] sequestered trypsin within a binary sol-gel-derived composite using TEOS and PEG. Ellerby et al. [74] entrapped other proteins such as cytochrome c and Mb in TEOS sol-gel. Later several proteins such as Mb [8], hemoglobin (Hb) [56], cyt c [55, 75], bacteriorhodopsin (bR) [76], lactate oxidase [77], alkaline phosphatase (AP) [78], GOD [51], HRP [79], urease [80], superoxide dismutase [8], tyrosinase [81], acetylcholinesterase [82], etc. have been immobilized into different sol-gel matrices. Hitherto some reports have described the various aspects of sol-gel entrapped biomolecules such as conformation [50, 60], dynamics [12, 83], accessibility [46], reaction kinetics [50, 54], activity [7, 84], and stability [1, 80],... 

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